1. Field of the Invention
The present invention applies to the field of wireless communications systems and, in particular, to paging user terminals.
2. Description of the Prior Art
Some communications systems, such as cellular voice and data communications systems, have several base stations in different locations available for use by mobile or fixed user terminals. User terminals can be cellular phones, PDA's, laptop computers, or any other wireless devices. When a base station needs to initiate communication with a user terminal, the base station pages the user terminal. When idle, the user terminal periodically listens for these pages.
The user terminal listens for pages on designated radio frequency (RF) resources. An RF resource can be, for example, an RF carrier, such as a 625 kHz band around a central frequency, e.g., as 800 MHz or 1.9 GHz, a timeslot in a TDMA (Time Division Multiple Access) frame, a frame, a CDMA (Code Division Multiple Access) code, or some combination of these resources. Thus, an RF resource can be thought of as a conventional communications channel. Similarly, if a conventional channel uses hopping, the resulting conventional logical channel can be thought of as a series of RF resources.
Some radio communications systems use frequency hopping on communications channels. Frequency hopping can reduce multipath fading. Frequency hopping can also be used to create interferer diversity, reducing the likelihood of prolonged severe interference on one channel.